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Questions tagged [nfc]

Near Field Communications - In antennae theory Far Field radiation is that RF energy that gets transmitted, Near Field is the RF energy that typically does not propagate , unless it is intercepted by a special antenna. It is used to transmit signals over short distances without transmitting widely, it is used in wireless communications for very short ranges on the order of meters and is harder to intercept because you have to be close.

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Easiest way to detect objects using DIY materials

I want to build a Scrabble board that detects tiles placed, mainly as a one off challenge and learning experience (i.e. not a commerical product). I haven't started building yet: I'm trying to work ...
Simon's user avatar
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RFID antenna measuring resonance frequency does not cover the theoretical value

I am looking to design a custom RFID antenna which operates at 13.56 MHz. I have designed the antenna using the NFC Design tool (link). Please see the parameters below: Figure 1: Antenna parameters ...
Dániel Határ's user avatar
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Does the minimum value of the S11 (return loss curve) at the resonance frequency depend on the resistance of the antenna?

I was trying to fabricate a flexible NFC antenna. Initially, I fabricated my design on a copper PCB. It worked perfectly fine with my NFC chip and facilitated NFC communication. I observed its S11 ...
Isuru Bhathiya's user avatar
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NFC Antenna Design for ST25R3911B in HFSS: Seeking Assistance with Antenna Parameters Extraction

I am currently working on antenna matching for an ST25R3911B NFC reader IC and using HFSS for simulation purposes. STMicroelectronics provides an antenna matching tool, and I am planning to use a ...
Amrit Aryal's user avatar
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NFC antenna design / Simulation

I'm looking for help with my NFC (13.56MHz) antenna design. I am using a NXP-NT3H2111 NFC IC and so far I have read through the application note and other research papers available online to try ...
Ethan25's user avatar
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NFC antenna design - moving from rectangular to circular

I'm working on a design using an NXP PN7150 NFC chip with PCB antenna. My initial prototype used their online tool for the antenna design, to generate the values for the matching network, however this ...
Scott Porter's user avatar
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How many coils does an NFC tag contain?

I'm trying to wrap my head around NFC tag inner workings. In particular I'm curious whether different coils are used for harvesting energy and to transmit data. This random NFC tag IC datasheet I ...
Nikolai Savulkin's user avatar
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NFC module commands/ TagLostException

I am trying to send commands and image data to an NFC module connected to an e-paper display and keep getting TagLostException, probably meaning the command is wrong. I have asked this question on ...
SatanasHammer's user avatar
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PN532 RFID Reader IC taking up 4mA even when there is no power applied

I have designed a custom PCB for one of my side projects. PN532 is interfaced with ESP32 over i2c. Goal is to have the system consume current in uAmps range when in deep sleep. I put ESP32 in deep ...
Hamza's user avatar
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Disable NFC tag so it does not trigger reader

Is there a way to disable (kill) the NFC tag so that it doesn't trigger the reader. Without physical intervention. My goal here is for the smartphone not to get triggered by a disabled NFC tag. ...
ProgZi's user avatar
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How to calculate the size of the goldcap in energy harvesting?

I want to build an NFC-transponder (NFC chip: ST25DV) which is powered over energy harvesting. How could I calculate the size of the goldcap (supercapacitor) or maybe a normal tantalum capacitor to ...
Mike's user avatar
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How can I make a double-sided NFC card, where the two sides read differently?

I'm trying to create a double-sided NFC cards, where the two sides read different things. So depending on which side you hold onto your phone, you get a different result. I've tried with a sheet of ...
Reactormonk's user avatar
3 votes
2 answers
925 views

Are those components mandatory?

I am building this circuit for an NFC component ST25R95 on a small PCB. I am wondering if I can disregard the marked components on the power supply (inductors and capacitors for filtering.) These ...
Anthony J Feghaly's user avatar
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mfrc522 Arduino library -> RFID ERROR: PCD_Authenticate() failed: Timeout in communication

I'm trying to do a project using RFID tags to store information to be retrieved later with another device. Kind of a storage memory. I've bougth several tags which I can write and read with several ...
Angel's user avatar
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Impedance match an NFC antenna to 50 Ω

I have a hard time understanding how I can impedance match a homemade NFC antenna to 50 Ω. My antenna is designed by calculating the inductance based on the dimensions, windings, and so on. R_ant is ...
Jesper Egsgaard Nielsen's user avatar
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NFC and magnet interference in a concrete piece

Do you know if both NFC and a magnet would work correctly in this scenario? I´m designing small pieces of concrete (imagine chess pieces) with three layers: magnet inside, NFC tag in the middle, and ...
Kaixo's user avatar
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Why is SPI described as output and UART as input in the MFRC522 datasheet?

I am currently trying to figure out why my NFC reader circuit with MFRC522 chip is not working and I stumbled upon this in the datasheet. In the section describing how to activate different digital ...
Lob Ster's user avatar
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What is a good loop probe to use for non contact measurements at 13.56MHz?

I have a receiving antenna (9 turn spiral, 1cm in diameter) that I would like to measure (inductance) wirelessly at 13.56MHz. While looking through application notes from ST and NXP semiconductors, I ...
Aayush Chadha's user avatar
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235 views

CCS/RF430FRL152HEVM: Trouble NFC value reading for RF430FRL152H

I am using the RF430FRL152HEVM kit for NFC communication with a mobile phone. I am building an app to read from this evaluation board and I am having trouble sending/reading an NDEF signal. I saw that ...
Saad Satter's user avatar
1 vote
1 answer
408 views

Calculate inductance and capacitance of a double layer antenna (RFID)

I want to design an antenna that will work with RFID NFC chip NHS3152. The NHS3152 IC specs are: IC capacitance at precise measurement conditions For this particular IC, there is a demoboard. Since I ...
Leo's user avatar
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Are there any NFC tags that act as a switch or relay?

From what I understand there is always an active (reader/writer) and a passive (tag) NFC device. Is it possible to have an NFC tag which is part of a circuit and works as a switch or a relay? I would ...
Andrej's user avatar
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Power minimization in a battery powered NFC Reader?

I have been trying to design a Battery powered NFC Reader using Quectel SC60 module with SAM interface. So , the problem is that in the reference design, LDO is always connected to VBAT thus draining ...
Curious Cosmopolitan's user avatar
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2 answers
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Secure Access Module (SAM) connected directly to MCU bypassing the reader IC

I have been trying to design an NFC Reader using a Quectel SC60 module with a Secure Access Module (SAM) interface. The problem is that in the reference design, the SAM is connected directly to the ...
Curious Cosmopolitan's user avatar
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Detection range of RFID with RC522/PN532

I need to read a tag in a range of about 5 to 10 cm (with 2 thin (~1 cm) layers between, one in plastic, the other in ceramic). I tested two devices: the RFID-RC522 and the PN532 (in NFC mode, reading ...
Dark Patate's user avatar
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1 answer
420 views

Does the signal to the NFC antenna require shielding?

My design requires a NFC antenna to be located on a different board and due to space limitations, a uFL connector can't be placed for a mini coax connection. A flex cable solves many of the design ...
pcbguy's user avatar
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1 answer
417 views

NFC and micro memory SD card

I am not sure if this is right place for this question. NFC bandwidth can go up to 50KB per second, and there are NFC business cards that have EPROM up to 8kb. Is there possibility to put micro SD ...
dejanmilosevic0's user avatar
1 vote
1 answer
267 views

Clarification on amplitude of observed NFC PICC response

I am using a simple pick up coil attached to an oscilloscope (and as pictured a Saleae Logic Pro 16) to monitor the NFC traffic between a reader (PCD) and ISO15693 tag (PICC). The reader is a PN5180 ...
paul_25's user avatar
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2 answers
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Help with electronic circuit for a bracelet that reads state from rfid tag attached to it and lights up the corresponding LED

I'd like to make a bracelet which has an RFID tag and LEDs inside of it. I made a device (using Arduino and rc522) that will categorise people's bracelets into one of 3 categories when it touches the ...
Rezi's user avatar
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1 answer
175 views

NFC tag antenna detection without an NFC chip

I need to build an application to detect an NFC antenna without an NFC passively powered chip. As we know, we can detect an NFC tag by powering the NFC chip inside this tag. It will then broadcast its ...
user176024's user avatar
3 votes
1 answer
334 views

NFC UID max read count

Documentations indicates a maximum number of read/write of 100 000 cycles for some passive NFC tags (for ex NTAG215, NTAG216, ...) Does this limitation apply if I only read the UID without any writes /...
angelodlfrtr's user avatar
1 vote
1 answer
882 views

Can smartphones power a MCU circuit through an NFC tag?

NFC tags are passive devices and get their power from the NFC reader/writer. For my question, I'm specifically asking for recent smartphones as NFC readers/writers. Does the phone transmit enough ...
fameman's user avatar
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1 answer
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NFC antenna booster

Hi I’ll get straight to the point... theoretically if I built an antenna loop that went around a door frame including under the carpet so I could walk through the loop, then connected the antenna to a ...
Brian foreman's user avatar
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How to tell what type of RFID tag?

I have an RFID tag for access to my apartment building that I would like to clone(buying one through strata would be 100s of dollars). I have a proxmark 3 easy and have cloned tags in the past with ...
bega2550's user avatar
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1 answer
200 views

Can i Increase the NFC range upto 50cm by making a bigger antenna? i only want to write data into a NFC enabled EEPROM?

As NFC are active upto 15cm range, i/m using a PN532 to write data into a NXP NFC enabled EEprom, which is successful, i want to increase its range by 2X by increasing the Power or size of Antenna for ...
JOHN JUSTEEN's user avatar
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140 views

Need RF advice (NFC antenna VS GND pour)

I'm currently working on a design who involve a NFC chip (ST24DV) who need to be on the board as it's used to communicate with a smartphone. Here is the picture of the antenna: There is a LED on the ...
Prof_Sims's user avatar
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2 answers
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Is an RF connector required for an NFC Tag?

I have an NFC tag application that uses an external antenna. The antenna itself has not been properly selected just yet, but my question is with regards to connecting the external antenna to the NFC ...
efox29's user avatar
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1 answer
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Using Bluetooth to rapidly connect and send data?

I have an idea for a distributed communication platform that I want to build. For my project, I would have many phones, and I would like to send ~20kb of data between each phone at a minimum range of ...
WhisperingShiba's user avatar
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1 answer
316 views

RFID (13.56MHz) tag properties depending on read distance

In a reader design i experiencing some problems with RFID tags. I've evaluated the different tags, and they all are made equally - the tag size, tag chip type, antenna and antenna geometry are ...
sgt_johnny's user avatar
2 votes
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1k views

Reading multiple RFID tags at the same time

Hi I've been working on a personal project for which i need to read multiple RFID tags in close proximity, something like 10-20 tags at once, I know RIFD tags can't be actually be read at the same ...
Riccardo Cecconi's user avatar
-1 votes
1 answer
248 views

What to be concerned about with NFC using external antenna located off board?

Working on an NFC application (NFC tag) and it looks like the NFC antenna will be located off-board. This is a sticker type of antenna. The concern that I am possibly having is that I need to run some ...
efox29's user avatar
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0 votes
1 answer
63 views

RFID Tags quality control

We have mutiple same-sized, same-tech RFID Tags (Mifare Classic), in the Field we have discoverd that some tags are less readable than others. For example, the distance is smaller or it takes more ...
sgt_johnny's user avatar
3 votes
2 answers
3k views

Would a magnet interfere with NFC devices in this scenario?

I am thinking about manufacturing an interactive chessboard as a personal project. The circular pieces (resembling more or less poker chips in shape) would contain NFC tags, so it is possible for the ...
francofeliardo's user avatar
2 votes
1 answer
1k views

Typically what range can an active powered type 5 NFC tag be written / read on iOS/Android

does anyone know the answer to the above - I am struggling to find out the information. I know that a type 5 tag can be read from 1.5 metres away in ideal conditions, but what can I expect from a ...
Dazza's user avatar
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1 vote
1 answer
493 views

Would a ground plane/traces impact NFC antenna performance?

I am building a PCB business card with an NFC chip and a WS2812B LED display (powered by a USB-C port, NFC is not connected to the LEDs). Right now I have a ground plane on the side of the antenna (...
Yonatan Avhar's user avatar
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1 answer
559 views

Read data from 125kHz tag and write into 433MHz remote

At the moment, I am opening the garage door via the 125khz key tag. I purchased a 433mhz remote. Also, I have a tool to read/write data from tags and I have used it in the past to copy key tags. I ...
sandalone's user avatar
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1 vote
1 answer
286 views

Low latency passive RFID solution?

I'm an embedded software developer working on a personal project using RFID. I'm attempting to read a passive 13.56 MHz tag moving at 100ft/sec. Given the limited range of passive tags, I'm looking ...
Chasen Johnson's user avatar
3 votes
2 answers
548 views

NFC Antenna Design/Matching without VNA

I would like to design a circuit around the W7002 antenna (Dataheet) and the NXP PN532 NFC Reader Chip. Since I never worked with antenna design before I do not have a VNA and I also don't have ...
Wiers's user avatar
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500 views

How to solder wires onto pins of an RFID chip?

I want to integrate a sensor with NXP's NHS3152 (datasheet). To do this I have to solder the wires onto the pins of the RFID chip. What tools should I buy to do this? What is a good reference to learn ...
Leo's user avatar
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3 votes
1 answer
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NFC - design of inductor/"antenna" made of PCB traces

I did a layout of a NFC PCB inductor/"antenna"(I know it is not one exactly) drawn only on top side copper (nothing drawn on other layers at inductor area), and I wonder if there will be a ...
abomin3v3l's user avatar
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NFC 13.56MHz RF - Use inductor in place of pcb trace made antenna

I need to make a NFC antenna on NFC tranceiver->LC filter->matching circuit->antenna. Inductance shows to be 1.5uH on an online calculator of nfc antennas. Can I simply just place a good inductor of ...
abomin3v3l's user avatar